Bearing



- DeC.7, 1937; c. F. SMART 2,101,759 BEARING Filed July 2, 1934 Cd-Zn BONDING ALLOY Cd- A; BEARING ALLOY Elma/whom 1. ,u Nir bf TAT Patented 79 .Clareiice F. 8mart, Pontiac. Mich, r *mGeneral Motors Corporation, Pontiac, Mich.,-

acorporaflon'otnela'ware v.

I "Applicants July teaser-mum ies; a.

iwlith the use of new and improved compositions or) alloys peculiarly adapted to meet'the exact ing 'conditions to which bearings are subjected in high speed machinery;

. Bearings'desjigned for juseunderrelatlvely high speeds andlprjessures, jm'tne principal bearings or internal .combustionengines, are g nerally w n: w h; ..=r i l u 031M fift s as .kjnownas Babbittfmetal, comprising,- tin and 1 small percentages of antimor'rv and copper. In operating engines at high speeds involving] high temperatures of the lubricant and bearing parts,

Qbabbitt surfaced bearings readily; reach afltemperature 'at which they becomeso weakened that disintegration occurs andsometimes they even reach the melting point. l

Inattempting; to overcom e ;th diifloulties incieo dent. to the use of Babbitt metals. I have found that an alloyfot cadmium with a relativelysmall content of silver "and preierably a very small.

addition of copper; and/or- -nickel possesses'rel fmarkable properties -lwhen-embodied inbearing eb surfaces. IThesilver contentldoes not become appreciably "eiiective until about 0.5% has been 1 added and the upper limit is in the neighborhood or 5%, although with a content 01 over; 13.5% it 'becomes increasingly dliflcult tomainalltain the homogeneity oi the alloy. The silver content that I have found mostYsatistactory is .approximately from 1.75%to 2.50%.

1 Either copper or nickel, or both, may be addedas hardening'agents but the amount should be, 35 relatively small, 'notexceeding about 1%" and f preferably being restricted to between 0.25%and 0.5%. 'The bearing alloy in its preferred composition would therefore contain:

. ,Percent Silver 1115- 2.50

Copper or nickel;.. 0.25 0.5 Cadmiumsubstantially the remainder or appro xlmatelylnn 97 '-98 1 .An alloy'suchas described melts as about 61m 1''. as compared to about 450). for ordinary Babbitt metals.- Its'hardness-may range from 38 to 50 on. the Brinell scale, whereas Babbitt metals range about 21 to 30. The new alloy'is o alsovery tough and maintainsits strength and 1 toughness at temperatures far above those at which ordinary Babbitt metals disintegrate or melt under conditions occurring in bearing service. It also possess ,;very high anti-friction 5s qualities in contact with steel journals. Its duinventionirelateslmbearings and 1 otmaking same andfis particularly concerned t ol ims. (closes-44,2) V I a a I to rabllity:hasbeendemonstrated by'the fact that a set oifbearlngs faced wlth this'alloy has outlasted three consecutive sets of babbitt-iacedbearings under identical conditions. 1

The application of the new alloy tobearing 5 members such as s1eeves, bushings, connecting rods,etc.', usually of steel, involves some difliculties infregard to the bonding of the alloy -to the base or backing member. ,I'have found it feasible to produce an extremely adherent and; in tact;

"tinning process employed to secure 'Babbitt metals toeabase. The coatingalloy I employ for this purpose comprises cadmiumjwith an addition of zinc or antimony. when antimony isfused the content may be about 7% (13% zinc f may be used in amounts of 5% to the pre- 20 I'redrange'beingabout 10% 15%. l

- The amount of bonding metal, as zinc, added to the cadmiumdto, constitutethe'fcoating or bonding alloyfdepends' somewhat upon. the amount of such metal permissible in the bearmg surface, since the bonding constituents ditfuse through the bearing alloy when the latter is cast upon the coatedsuriace. I find; for example, that the bearing metal givesmost satls-' factory service it the-amount oi zinc presented at its surface'is not over about 0.25%. Therefore, although the zinc or antimony is required to provide coherence or alloying with the surface-of the base, as bronze or ferrous metal, and also serves to protect the cadmium-ingredient from oxidation, its amount should be restricted. as indicated. I .A process oi' makinga bearing member embodying the invention may be described briefly as follows. A foundation or base of strong metal as 40 bronze or steel, is first cleaned by the usual methods, as by removing rust, grease, etc., then fluxed as usual for metal coating,.as with zinc chloride and hydrochloric acid; The coating or bonding alloy is then applied. This may be done by dipping the base in a molten bath of the bonding alloy which is maintained at a, temperature of BUY-700' F. An immersion of about 30 seconds will usually be sumcient to client coating and bring the temperature of the base up to near that of the bath. The bearing surface is'then cast upon the base while the latter is still hot, the fused alloy being at a temperature of about 709?- 750" 1". After cooling. the bearing surface'is finished to the desired dimensions. The final 2 I thickness of the bearing alloy coating need not be over about .010 inch for use, for example, in

connecting rod bearings for internal combustion engines for automobiles.

The bondv between the bearing alloy and-. the base is so strong and the bearing alloy itself is so tough that a steel base thus surfaced may be bent substantially upon'itself without cracking .the alloy or fracturing the bond. These properties, in addition to the relative melting points of the bonding alloy and the bearing alloy, render it possible to make bearing members, such as sleeves or bushings, by first making ablank in theform of sheet material, and then shaping the material to the desired form. For this purpose I prefer to cast the bearing alloy in bar form and cold rollit with any necessary intermediate annealing, to eil'ect the desired reduction in thickness. its physical properties especially in regard to its compactness and tensile strength. The thin sheet may then be placed upon a sheet of backingmaterial, as sheet steel, with bonding alloy interposed, as by previously coating the basesheet, and

the bonding brought about by pressure at a temperature approximating 550 F. The composite sheet so produced may then be severed into blanks of suitable size and formed into bearing members by customary processes.

The accompanying drawing illustrates a bearing member made in accordance with the inven-v tion. The base or backing element I is indicated as steel, the intermediate layer 5 of bonding alloy, which, of course. substantially. disappears in the completed article by diifusion into the base .metal and the bearing alloy, is indicated as The cold working of the metal improves.

description except as required by the appended claims.

I claim 1. A bearing comprising a base of relatively I hard and strong metal and a facing integrally bonded thereto. said facing comprising an alloy of cadmium with relatively small additions of silver and a hardening metal.

2. A bearing as inclaimi, said alloy containin8.1.75% to 2.50% silver and 0.25% to 1% of a hardening metal.

3. A hearing comprising a steel backing and an anti-friction facing integrally bonded thereto,

said facingcomprising an alloy of cadmium with relatively small-additions of silver and hardening metal.

, cadmium.

6. A bearing comprising a base of relatively hard and strong metal, a facing of an alloy of cadmium and silver and an intermediate bonding layer comprising an alloycontaining cadmium and a metal tending to adhere to the said base.

7.1L bearing as set forth in claim 6, thebase metal being of ferrous metal and the intermediate bonding layer-comprising an alloy of cadmium and zinc.

8. A hearing alloy consisting of si1ver0.5 to 5%, a metal of the class consisting of copper and nickel in amount sufllcient to impart appreciable hardness but not in excess of about.1% and the balance substantially cadmium.

9. A bearing alloy consisting of silver 1.75 to 2.50%, a metal -of the class consisting of copper and nickel 0.25 to 0.5% and the balance substantially cadmium.

10. A hearing comprising a surface layer of a metal alloy consisting chiefly of cadmium and including .5 to 5% of silver, the alloy including a small proportion of a hardening metal.

CLARENCE- F. SMART. 

